BCM1250/BCM1125/BCM1125H
User Manual
10/21/02
B r o a d c o m C o r p o r a t i o n
Page
108
Section 6: DRAM
Document
1250_1125-UM100CB-R
shows possible memory clock frequencies for different divide ratios and CPU clock speed.
shows the percentage difference for the closest frequency below some common DIMM frequencies for each
of the CPU clock speeds (entries are left blank if the closest frequency is more than 10% under the required
one)
600
300
66.7
75.0
85.7
100.0
120.0
150.0
550
275
61.1
68.8
78.6
91.7
110.0
137.5
500
250
55.6
62.5
71.4
83.3
100.0
125.0
450
225
50.0
56.3
64.3
75.0
90.0
112.5
400
200
44.4
50.0
57.1
66.7
80.0
100.0
Table 58: Clock Speed
(Cont.)
CPU Clock
ZBbus
Clock
Memory
Clock 4.5:1
Memory
Clock 4:1
Memory
Clock 3.5:1
Memory
Clock 3:1
Memory
Clock 2.5:1
Memory
Clock 2:1
Table 59: Percent Deltas from Popular DIMM Frequencies
CPU Clock
ZBbus Clock
133 MHz DIMM
Clock
143 MHz DIMM
Clock
166 MHz DIMM
Clock
183 MHz DIMM
Clock
200 MHz DIMM
Clock
1200
600
0.0
-6.8
-10.0
-6.5
0.0
1150
575
-4.1
-
-1.4
-
-4.2
1100
550
-8.3
-3.8
-5.7
0.0
-8.3
1050
525
-1.5
-8.2
-10.0
-4.5
-
1000
500
-6.2
-0.1
0.0
-9.1
0.0
950
475
-
-5.1
-5.0
-5.0
900
450
-3.5
-10.1
-10.0
-1.8
-10.0
850
425
-8.9
-0.9
- -7.3
-
800
400
0.0
-6.8
-4.0
- 0.0
750
375
-6.2
- -10.0
- -6.3
700
350
-
-2.1
-
-4.5
-
650
325
-2.5
-9.1
-2.5
- -
600
300
-10.0
-
-10.0
-
-
550
275
-
-3.8
-
-
-
500
250
-6.2
- - - -
450
225
-
-
-
-
-
400
200
-
-
-
-
-